Ola Sanderfelt

A woman is found murdered in a closed amusement park. A young couple who happen to be there at the same time become, without their knowledge, suspects for the murder. They are chased by a large number of police but only Martin Beck believes them to be innocent.

A bomb threat is called in to a police station in Stockholm. The police bomb squad blows the briefcase to pieces and it looks like false alarm, until a baby is found inside. Soon, e-mails are sent out to every newspaper about the nasty situation that the police had tried to keep secret. Will the police ever overcome the "Monster"?